As shown in FIG. 2, a typical cable television network includes a signal headend (201). The signal headend (201) is a facility maintained by the cable television company from which the cable television signal is sent to subscribers over the cable network (203).
Each subscriber to the cable service is typically provided with a set-top terminal (202). The set-top terminal (202) is a box of electronic equipment that interfaces the subscriber's television, and possibly other electronic equipment, with the cable network (203).
The signal headend (201) broadcasts the cable television signal over the cable network (203) to the population of set-top terminals (202) possessed by individual subscribers. In addition to being connected to the cable network (203), each set-top terminal (202) also has a connection (204) to the subscriber's television and/or other electronic equipment to allow the subscriber to make use of the signals from the cable network (203).
The set-top terminals (202) include electronic memory (206) and a computer processor (205) which is programmed using the memory (206) to process and make use of the signals transmitted by the headend (201) over the cable network (203). The set-top terminals (202) may be programmed to provide a variety of services including decoding premium cable channels and providing electronic programming guides.
Periodically, as the cable system evolves, new features may become available or signal distribution may be refined in such a manner that the programming in the set-top terminal (202) needs to be updated in order to allow the terminal (202) to continue to provide the services of the cable system to subscribers with peak efficiency. If a technician must visit the home of each subscriber to upgrade the programming in the set-top terminals (202), the implementation of the upgrade becomes time-consuming and expensive.
To avoid these problems, new programming for the set-top terminal (202) can be transmitted to the terminal (202) over the cable network (203) itself. In this way, upgraded programming and data can be distributed automatically from the headend (201) without requiring a visit to each set-top terminal (202) individually.
However, additional problems arise in downloading updated programming and data over the cable network (203) to the set-top terminals (202). For instance, in conventional systems, when a set-top terminal (202) detects that data or updated programming is being offered by the headend (201) for downloading, the set-top terminal (202) automatically accepts the download and may erase existing data or programming from memory (206) in favor of the newly-received data or programming.
This will result in an interruption of service because the set-top terminal (202) will be unable to continue providing its normal functions while it is receiving new data and programming to replace that which has been erased. If the subscriber is attempting to watch television or use the set-top terminal during this time, the subscriber may be interrupted. These interruptions of the set-top terminal's normal functions may be completely unnecessary if the set-top terminal already happens to have the same version of the data or programming being offered for download over the network (203).
It may be possible to minimize the impact of this problem by only broadcasting updated data or programming to the set-top terminals (202) during off-peak hours when television is not commonly watched, such as between one and five a.m. However, this requires additional staffing for the headend facility (201) during those hours which is expensive. Additionally, there are subscribers who use their television service during all hours, even if only to record programming which will be watched later. Therefore, the interruption of set-top terminal functions during data download posses significant and sometimes unnecessary problems.
These problems may be exacerbated if the updated programming or data is broadcast to the set-top terminals (202) on an in-band channel as is anticipated in the near future. If the incoming data is on an in-band channel, the set-top terminal (202) will have to change the channel from the one the subscriber is watching or recording in order to tune to the channel over which the download is being provided. This will make normal television viewing and recording during the period of the download impossible.
Similar disruptions of service can occur when the set-top terminal is switching from running existing programming to the execution of new programming received in a download from the headend (201).
Consequently, there is a need in the art for a method and apparatus for preventing disruptions in cable television service due to the downloading and implementation of updated programming or data to the set-top terminal via the cable network.